Yao Longfei, Fu Kuo, Liu Guofeng
School of Chemical Science and Engineering, Advanced Research Institute, Tongji University, Shanghai 200092, People's Republic of China.
ACS Appl Mater Interfaces. 2023 Aug 30;15(34):40817-40827. doi: 10.1021/acsami.3c10358. Epub 2023 Aug 15.
It is important to identify the effect of assembly and aggregation on the chirality transfer and energy transmission in supramolecular polymer system, since the unordered aggregation is insufficient to promote luminescence enhancement and chirality transfer, even causing the negative effect. Another key issue is to identify the solvent effect on hierarchically chiral self-assembly. Herein, we designed an AIE-core based building block, tetraphenylpyrazine-cholesterol (TPP-Chol), to explore how the solvent component influences chirality transfer and energy transmission of its aggregates and/or assemblies. Interestingly, the hierarchical assembly behavior was realized in the mixture of MeOH/CHCl highly dependent on the MeOH content. During the solvent-directed hierarchical assembly, the morphologic transformations, such as nanoribbons with a width of 150 nm, twisted nanoribbons with helical pitch of 420 nm, nanoribbon clusters, and microflowers with an average diameter of 5.5 μm, were realized with obvious chirality amplification for both circular dichroism (CD) and circularly polarized luminescence (CPL) measurements. The hierarchical assembly of TPP-Chol was also demonstrated by a time-dependent CD test. The work points out the complexity and dynamic of hierarchically chiral self-assembly regulated by the solvent effect, which would be helpful for the development of supramolecular materials with enhanced CPL performance and dynamic chirality.
识别组装和聚集对超分子聚合物体系中手性转移和能量传递的影响非常重要，因为无序聚集不足以促进发光增强和手性转移，甚至会产生负面影响。另一个关键问题是识别溶剂对分级手性自组装的影响。在此，我们设计了一种基于聚集诱导发光（AIE）核的构建块，四苯基吡嗪-胆固醇（TPP-Chol），以探索溶剂成分如何影响其聚集体和/或组装体的手性转移和能量传递。有趣的是，在MeOH/CHCl混合物中高度依赖于MeOH含量实现了分级组装行为。在溶剂导向的分级组装过程中，实现了形态转变，如宽度为150nm的纳米带、螺旋间距为420nm的扭曲纳米带、纳米带簇以及平均直径为5.5μm的微花，对于圆二色性（CD）和圆偏振发光（CPL）测量均有明显的手性放大。TPP-Chol的分级组装也通过时间相关的CD测试得到了证明。这项工作指出了由溶剂效应调节的分级手性自组装的复杂性和动态性，这将有助于开发具有增强CPL性能和动态手性的超分子材料。
